If you want a loud noisemaker, you could always buy one of those compressed air horns, but if you prefer something that you can reuse over and over, check out HABU’s build – which uses a modded cordless power drill and a small compressor pump to blow air through a pair of horns.
Looking for the loudest Bluetooth speaker you can buy? The DiamondBoxx XL2 has a dozen amps and 14 speakers, that can crank out up to 660-watts continuous, or 1000-watts peak power with minimal distortion. It runs up to 20 hours per charge, and while it does have a carrying handle, it’s not exactly portable at 52 pounds.
(Loud) Here’s two minutes of porn for rocket junkies, as private space exploration company Blue Origin tests out one of their BE-4 rockets which can produce 550,000 lb-ft. of thrust. And if you think that looked powerful, keep in mind that this was just at 65% of full throttle.